ABSTRACT The overall objective of the Core E: Mouse Immunization/Challenge Core is to provide centralized testing of candidate gonorrhea vaccines developed by Projects 1, 2, 3, and 4 in immunization/challenge studies to identify the most promising gonococcal vaccine antigen(s) and candidate vaccines. The standardization of the mouse immunization/challenge experiments by Core E for vaccines developed by all projects is critical for the overall success of the Gonorrhea Vaccine Cooperative Research Center (GV CRC). To accomplish the goals of Core E, centralized vaccine testing will be performed in the following three female mouse infection models with accompanying statistical analyses to identify correlates of protection: 1) Lower Reproductive Tract Model: Core E will conduct initial testing of all vaccines in a well-established mouse model of Neisseria gonorrhoeae (Ng) lower reproductive tract (LRT) infection; 2) Upper Reproductive Tract Model: Vaccines that show efficacy in the LRT model will be tested in a novel model of Ng upper reproductive tract (URT) infection to verify efficacy in both anatomical sites; 3) Gonorrhea/Chlamydia Coinfection Model: Final testing will include evaluation in a Ng/Chlamydia muridarum coinfection model to determine whether efficacy is maintained in the context of simultaneous infection with another immunosuppressive organism; 4) Statistical Analyses for Correlates of Protection: Cox proportional hazard regression analyses will be performed on combined data generated by the Cores C, D and E to identify correlates of protection. This centralized testing and analyses of the vaccines will ensure that the best gonorrhea vaccine is identified for advancement into clinical trials.